Conventional jaw chucks as associated with rotary machine tools, such as lathes, employ a rotatable chuck housing which mounts a plurality of radially displaceable jaw carriers, and these in turn removably mount jaws which are adapted for gripping a workpiece. The jaws assume many shapes and sizes, and are interchangeably mountable on the jaw carriers to facilitate use of the chuck in conjunction with a wide variety of workpieces. One conventional mounting technique for removably securing jaws to jaw carriers involves the use of threaded fasteners, specifically screws or bolts. Such arrangements, however, are time consuming when changing of the jaws is desired, increase the size, mass and complexity of the jaw arrangement, and often result in structures which reduce the rigidity of the jaw assembly but increase the undesired centrifugal force effect.
In an attempt to facilitate the mounting of jaws on carrier assemblies, several arrangements have been developed employing a carrier assembly having main and auxiliary carrier members which are relatively movable with respect to one another to facilitate the mounting or removal of the jaw. Most of these arrangements, however, have still possessed features which have resulted in structural and operational complexities.
One such arrangement is illustrated by U.S. Pat. No. 3,868,120 (Blattry et al). This patent illustrates a main jaw carrier having an auxiliary carrier slidably mounted thereon. In this arrangement, however, all of the opposed surfaces of the jaw carriers must be rigidly joined together to permit proper utilization of the arrangement, and hence this restricts the changing of the jaws.
Another arrangement is illustrated by U.S. Pat. No. 3,219,356 (Wilterdink et al) which discloses a rotary cam for locking the upper and lower jaw carrier portions together, although the joining of the carrier portions is through interfitting serrated surfaces. This type of arrangement increases the manufacturing cost and decreases the efficiency of the apparatus as regards its convenience of use.
Other arrangements of this general type are disclosed by U.S. Pat. Nos. 3,833,232, 2,667,358, 3,679,221 and 4,352,500. The arrangements of these latter patents involve complex structural and functional arrangements which hence minimize their desirability.
Still another arrangement is illustrated by U.S. Pat. No. 4,667,971 owned by the Assignee hereof. This '971 patent does illustrate therein a fast change top jaw system for a chuck which has proven highly desirable in terms of its ability to permit rapid changing of top jaws. This arrangement, however, wherein the master jaw and a spring-urged auxiliary jaw define a dovetail projection for cooperation with a dovetail groove in the top jaw, still possesses a greater number of parts and components than is ultimately desired. Further, and more significantly, this latter arrangement, while highly desirable for inside-diameter gripping, is less suitable for outside-diameter gripping because of the structural and functional arrangement of the fast-change locking structure.
Accordingly, this invention relates to an improved jaw carrier arrangement for permitting rapid and efficient removing and/or mounting of a top jaw, and particularly to an improved jaw carrier arrangement which is highly suitable for use with top jaws which engage either inside diameter or outside diameter surfaces of a workpiece while still providing for secure and rigid gripping of the workpiece in a efficient but dependable manner. This improved jaw carrier arrangement is also believed to possess an improved and more desirable structural and functional arrangement so as to facilitate both economical manufacture and efficient utilization thereof.
In the improved jaw carrier arrangement of this invention, there is provided a main jaw carrier which removably mounts thereon a top jaw. For this purpose the main jaw carrier has a bore therein which opens outwardly through the front face of the jaw carrier for receiving therein a rearwardly projecting support post provided on the top jaw. A clamping structure is provided on the main jaw carrier for creating a wedgelike clamping engagement with the post of the top jaw to securely and rigidly hold the top jaw in snug engagement with the front face of the chuck. The clamping arrangement includes radially inner and outer clamping members having opposed riblike wedges which project inwardly toward the post for engagement within wedgelike grooves which are formed on diametrically opposite sides of the post and extend perpendicularly across the post in generally parallel relationship to one another. The inner and outer clamping members are controlled by rotation of a threaded spindle which causes simultaneous movement of the clamping members in opposite directions, whereby the clamping members move inwardly so that the ribs thereon engage the grooves on opposite sides of the post to securely clamp the post therebetween, and at the same time effect a snug drawing in of the post and of the top jaw against the front face of the chuck. The clamping which occurs on opposite sides of the post, which opposite sides are disposed radially inwardly and outwardly relative to the chuck, provide a rigid securement of the top jaw so as to permit the top jaw to grippingly engage either an inside diameter or an outside diameter of a workpiece.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.